Redmine

I'm creating a custom field for file upload.

This field only uploads 1 file, but I awant to to upload many files to the same field
(here only 1 file)
Is it possible?

When I try to drag and drop multiple files to this field i get folowing error:

Is there a way to make it so that multiple file could be uploaded simultaneously to custom file field through drag'n'drop or file selection dialog?

Information about redmine:

RAILS_ENV=production bin/about

sh: 1: hg: not found
sh: 1: cvs: not found
sh: 1: bzr: not found
Environment:
Redmine version 5.1.1.stable
Ruby version 3.0.1-p64 (2021-04-05) [x86_64-linux]
Rails version 6.1.7.6
Environment production
Database adapter Mysql2
Mailer queue ActiveJob::QueueAdapters::AsyncAdapter
Mailer delivery sendmail
Redmine settings:
Redmine theme A1 (includes JavaScript)
SCM:
Subversion 1.14.1
Git 2.30.2
Filesystem
Redmine plugins:
redmine_agile 1.6.4
redmine_checklists 3.1.22
redmine_contacts 4.3.6
redmine_more_previews 5.0.6
redmine_questions 1.0.5
redmine_resources 2.0.1
redmine_zenedit 2.0.6
redmineup_tags 2.0.14